Printing-telegraph-exchange system



u 1,637,324 5ml? 26 1927' D. B. PERRY PRINTING TELEGRAPH EXCHANGE SYSTEM Filed Sept. 9, 1925 5 Sheets-Sheet lv PRINTING l',IEIJEHKPH EXCHANGE SYSTEM med'sept. 9,1925 5 sheets-sheet 2 Hkn n nl n N y Wg Affy D. B. PERRY PRINTING TELEGHAPH EXCHANGE SYSTEM July 26 1927. 1,637,324

Filed sept. 9, 1925 5 sheets-sheet 5 u u n u u n n n 1| n n u u n n 1| n n lL- u u n n n u n u n n u u1u n 1| n n n Il u' n n n Il Il II II ll Il il Il I| ll Il Il` Il Il II II 1| n u n Il n by w Af?? July 26,1921. V 1.637,324

D. B. PERRY PRINTING TELEGRAFH EXCHANGE SYSTEM Fuga sept. 9, ms 5 sheets-sheet 4 E Q 5 i a ,Q v

July 2j'6 `1927. 1,637,324

D. B.. PERRY PRINTING TELEGRPH EXCHANGE SYSTEM Filed Sept. 9, h1925 5 Sheets-Sheet 5 v by Af/y "DONALD B. EERRY, OF YONKERS, NEW YORK, ASSIGNOR TO AMERCAN TELEHONE ND .EELEGRAPHv CDMPANY, A CDRPORATION 0F NEW YRK.

PRINTING-TELEGRAPEEXCHANGE SYSTEM.

Application-med September 9 1925. Serial No. :$5,327.

rlhis invention relates to printing telegraphsysteins and more particularlyto tele graph systems wherein automatic switches are employed :tor the establishment of channels of telegraphic communication'.

The invention has for its main object to provide a telegraph exchange system which utilises automatically and directively operable switches for establishing telegraphic connections, whereby the flexibility and ef. iciency of telegraph systems are greatly increased.. y

Heretofore, in printing telegraph systems where each subscribers station is equipped with motor driven printing mechanism it has heen the practice to signal. the subscriber at a called station over special circuits before the operation of the printing apparaf vtus thereat, in' order that said apparatus might he put in movement.

@ne of the features of this invention is the provision of means whereby the rinting operations at a called station may immediately ensue )upon the completion of a connection with said called station, without the manipulation of any switching devices thereat.

Another. "feature ofthe invention relates to the means 'for controlling the printing .apparatus driving motors over a commumcation circuit, thus eliminating the necessity -tor using extra controlling-wires.

A still further feature relates vto a telegraph system tor establishingso-called com terence connections, enabling a callingsubscriber to directly control the establishment ot simultaneous telegraphic connections with a plurality of other stations, whereby -the saine message may he received at many stations simultaneously. l

. Another teature of the invention relates to the means 'tor releasing a connectorI switch when a desired line is busy without releasing the. coimection, thus permitting a calling station to reoperate the released connegtor to 'complete connection with 'any other idle" station.

A still 'further feature relates to a printingtelegraph exchange system wherein a telegraph repeater functions to control the operation of automatic switches and to repeat telegraph signals to a plurality oftelegraph receiving devices.

Referring to the drawing, Figure 1 shows `a subscribers station with the necessary vceiving printer with associated driving motor and control circuit therefor. This ligure also shows a subscribers individual line switch and the associated master control switch.

Fig. 2 shows a connector switch in which the called euh-station lines terminate..

Fig. 3 shows a special connector switch which is controlled by a calling subscriber to establish a conference circuit. ',lhis figure also shows a telegraph repeater for controlling the associated special connector switch, and for repeating telegraph signals to called stations.

lfig. l shows a plurality of subscribers stations withassociated apparatus similar t0 that illustrated in Fig. l.

Fig. 5 shows ranother' special connector switch and associated repeater circuit simi.- lar to corresponding apparatus disclosed in Fig. 3.

Fig. 6 is a diagram showing the manner in which the several gures of the drawing are to be arranged for the purpose of obtaining a unitary disclosure et a preferred form of carrying out the invention.

ln the drawing there are illustrated, in comparative detail, two printing telegraph stations, and 400. rllhese stations are connected with the central oflice by means of the line wires 101 and. 401 respectively. At thecentral station, the lines, as calling lines, terminate in contactspt line switches, for example, switches 102 and 402. The lines also have an appearance, as called lines, in connector switches shown in Figs. 2, 3

' and 5, it being understood that each line is,

multipled Vto appear before corresponding 'sets lof terminals in all the connector switches. For example, line 101 is multipled to appear in terminals 201 of switch 200 and in correspondingly positioned terminals of connector switches 300 and 500.

Extending' from each of the line switches are trunks which terminate in the movable contacts of the connector switches. For example, trunk 103 is one of a plurality of trunks which lead from line switch 102. 4This particular trunk terminates in the brushes 202 and 203 of connector switch 200. lt will he understood that as many tru and connecquire.

message recorded on several printers at the` same time, a special code is dialed which, for convenience of description, may be called the conference number. This code is dialed lprior to the dialing of impulses correspondingl to the numbers of the desired subscribers stations. The dialing of'this code number results in the association of a predetermined number of repeater connectors with the extended line. The'number of repeater connectors associated with each conference knumber may vary as conditions re- The conference circuit -comprises a number of single Morse telegraph repeaters, each associated with a connector switch. For example, repeater 301 is associated with, and

V controls the operation of connector switch sage recorded on 300, While repeater 501 is associated with connector switch 500. The subscriber by means'iof his dial maygeause each repeater connector in succession to operate to associate the printers of any of the other stations with the extended line.

For the purpose of enabling a better understanding to be attained of the'operation of the system, a detailed description will first be given of the manner in which a message is recorded at a distant station without the use of a repeater connector. Subsequently hereinafter, a description will be given of the manner in which a subscriber may establish a conference circuit to cause his message to be printed simultaneously at a plurality-of different stations.

Detailed description.

Let it be assumed therefore that the subscriber at station 100 desires vto have a mesrinter 430 at station 400. It will be noted t at the line 401 from this latter station terminates in the eighth level in connector switches 200, 300 and 500, etc. The subscriber at station 100 operates the switch 118, which at its contacts breaks the energizin circuit of motor control relay 109 whic thereupon releases. It is to be noted `that relay 109 is normally o erated over a circuit traceable from battery t rough resistance 106 and the lower inner contacts vvof magnet 105, upper conductor of line 101,

right ynormal contacts of key 118, winding of rela. 109, to around. Rela 109 upon being eenergized; as describe closes its contacts to complete the circuit from the source of power 110 to operate the printer driving motor 111.

The manipulation of key 118, as mentioned, also completes a circuit from ground at the contacts of relay 104, through the winding of relay 120, lower outer contacts of magnet 1 05, lower conductor of line 101, normally closed contacts of dial 107, through the printing and transmitting apparatus, make before break contacts of key 118, upper conductor of line 101 to battery at the lower inner contacts of magnet 105. lRelay 120 operates in this circuit and closes an ob' vious circuit for the lower winding-oflmagnet 105, whereby plunger 112 operates the contact set associated with theidle trunk 103. Line switch 102 is of the pre-selector type and is under control of the master switch shown diagrammatically within the rectangle 125. The master switch causes the plunger of each idle line switch to be positioned before sets of contacts corresponding to an idle trunk. Magnet 105 when operated as described, opens the energizing circuit of relay 120, but relay 120 is of the slow-to-release type and is so adjusted as to maintain its armatures attracted until relay 204 operates as hereinafter described, to provide a holdin circuit for magnet 105,. Simultaneously with `the actuation of plunger 112, a circuit is completed from battery through the left winding of relay 113- to ground at the left inner contacts of the line switch. Under control of relay 113, the master switch causes the plungers of other idle line switches to be positioned before the bank contacts corresponding to an idle trunk. Should the trunk su'cceeding trunk 103, and associated with contacts 126, 127, be busy, the conductor corresponding to conductor 128 is grounded, thus maintaining relay 113 energized. This condition obtains until the brushes 131 and 132iare positioned before the test terminals of an idle trunk, whereupon the absence of ground on the test conductor, thereof, brings about the release of relay 113 and the prevention of further movement of the idle line switch plungers. The operation of plunger 112 also completes a circuit from battery through the winding of the connector vline relay 205, upper middle back contacts of relay 206, lower winding of differential relay 207, right inner contacts of the line switch, through the. dialing and printing apparatus at the substation 100, returning through the make-before-break contacts of key 118, right. outer bank contacts of switch 102, upper winding of dierential relay 207, uppermost back contacts of relay 206, to ground at the contacts of relay 208. yRelay 205 operates in this circuitsbut relay 207 being dierentially wound maintains its armature in its retracted position. A circuit is now closed for the release control relay Iso 204, traceable from battery through the winding of said relay, front contacts of relay 205. to ground at the contacts of relay-l nals of all the connector switches in which line 101 appears, to render thisline busy. A steppin circuit is now prepared and may be traced rom battery through the winding of vertical magnet 209, slow-torelease relay 210, uppermost contacts of the oit-normal switch 211, lowermost contacts of relay 204, to the back contact of line relay v205.

The subscriber now actuates the impulse sending device 107 to transmit a series of eight impulses corresponding to the level in the connector switches in which the line 401 terminates. At each interruption of the line 101, by the impulse sender 107, relay 205' releases, but relay 204 is so adjusted as to maintain its armatures attracted during the intervals between successive impulses of a series. On the first retraction of the arma-y ture of relay 205, the stepping circuit which was partially traced hereinbefore is now completed through the back contact and armature of relay 205, to ground at the back contacts of relay 206. Brushes 202 and 203 are thus raised into cooperative relation with' the irst level of the associated .bank terminals. The original circuit for energizing magnet 209 is broken when brushes 202 and 203 move off normal, but another circuit is prepared for thesucceeding im-v pulses of the series. This circuit may be traced from battery throughvthe windingr of magnet 209,.-winding and front contacts of relay 210, middle contacts of the ofi-normal switch 211. lower outer front contacts of f relay 204 to ground as previously traced.

When the brushes 202 and 203 move .from their normal position, a circuit for release magnet 216 is prepared, but this circuit 1s notcompieted so long as relay 204 remainsl energized.

At'the' termination of the first series of impulses, relay 205 remains energized for a sutlicient interval to bring about the release ot relay 210, whereupon the stepping circuitis transferred to the rotary magnet 213. The subscriber now manipulates device 107 to send a series of six impulses corresponding to the row in which line 401 terminates. Each time rclay205 retracts its armature in response to the transmission ot an impulse, a circuit is completed `from battery through the winding of rotary magnet 213, back contacts of relay 206, and in parallel therewith from battery through the winding of. slowto-release relay 212, lower inner contacts of relay 214, back contacts of relay 210, middle contacts of the ott-normal switch'211, lower outer frontY contacts of -relay 204, back contacts of relay 205, to ground at the contacts of relay 206. vUnder control of relay 205 and magnet 213, brushes 202 and v203 are moved into cooperative `relation with the terminals 221.

At the end of the second series of impulses, magnet 213 deenergizes, but relay 212I being oli' the slow-to-release type maintains its armatures attracted for a suiiicient interval to allow a test to bemade of the line 401. For this purpose, a circuit is completed from battery through the winding of relay 214, lowermost contacts of relay 206, upper front contacts of relay 212, brush 203 to thel conductor 403 of the line 401. If the line 401 1s busy, conductor 403 is grounded in a manner similar to that described in connection with the grounding of conductor 115. Under this condition, relay 214 operates. .After an interval, relay 212 releases, but a locking circuit is provided for relay 214, traceable from battery through the winding of said relay, lowermost contacts of relay 206, upper normal contacts oi' relay 212, upper front cont-acts of relay 214, to ground at the lower inner contacts of relay 204. The operation ot relay 214 opens the stepping circuit to magnet 213 so that succeeding impulses will not affect the position of brushes 202 and 203.4 .At this time also, a circuit is closed .from groundV through the contacts of the mterrupter 215, winding of relay 208, lower front contacts of relay 214, to battery at the contacts of relay 212. Each time that relay 208 operates under control of interrupter 215, the communication circuit hereinbei'ore traced through the upper winding of diierential relay 207 is opened. The interrupter 215 is provided 'with suitable conducting and insulating segments so arranged that impulsesl corresponding to the character B are sent over the line 101 to effect the recording of this character on the receiving printerat station 101. The interrupter segments may also be arranged to cause impulses to be sent, corresponding to the word busy which may thereupon be recorded on the receiving printer.

The, subscriber on recognizing the busy signal, restores key 118 and opens switch 108 for a short interval. The circuit comprising the `windings or" relays205 and 207, as hereinbetore traced, is nowv open. Relay 205 accordingly releases. Relay 205 in'turn opens the energizing circuit of release control relay 204 which, after an'interval, `also releases. When relay 204 releases` a. circuit is completed from battery through the windn afl. .em

ing et release magnet 216, lower contacts of the oil-normal switch 211, lower back contacts of relay 204 and relay 205, to ground at the contacts ot relay 206. Under control of the release magnet 216, the brushes 202 and 203 .are restored to their normalV position whereupon the circuit through the lower contacts oit the on normal switch is open and the brushes are brought to rest in their normal position. 1When relay 204 releases, ground is removed from the conductor 119, resulting in the release of magnet 105 and the withdrawal of the plunger 1121om the associated bank contacts. Relay 204 also opens the 'holding circuit of relay 214 which thereupon releases. The connector switch and associated relays are thus completely restored to normal. 1When magnet 105 releases as above described the energizing circuit `of relay 109 is closed, and this relay operates to open the motor circuit. The stopping of the motor serves as a signal to the subscriber at station 100 that key 108 may be reclosed. o

Should the line 401 be' idle when relay 214 is connected to the conductor 403, as hereinbetore described, said conductor is ungrounded and relay 214 remains normal.

Accordingly, when relay 212 releases, a cir?- cuit is 'completed from battery, through the upper winding of magnet 405", conductor 403, brush 203, upper back contacts of relay 212, lower winding of relay 206, upper back contacts of relay 214 to ground at the lower inner contacts of relay 204. Relay 206 op` crates in this circuit and immediatelycloses a locking circuit for itself traceable :from battery, through the upper winding and locking contacts of said relay to ground at the upper contactswof relay 204. However, the current through the upper winding of magnet 405 as above traced, is insuiicient to cause the actuation ofthe plunger 41,2, but

the energization is suiiicient to cause the lower armatures of this magnet to be attracted. r1`he `opening of the lower inner contacts of magnet 405 opens the normal energizing circuit of the motor control relay 409, which thereupon releases and connects the source of power 410 with the motor 411. The original energizing circuit of relay 204 is opened when relay 206 operates. A substitute holding circuit for the former relay is now completed from battery, through the winding thereof, back contacts of relay 207 to ground at lower front contacts of relay 206. Relay 206 also extends ground through its lower inner contacts to brush 203, thence to conductor 408 to maintain the lower armatures of magnet 405 in their attracted position and to render line 401 busy. Relay 206 in addition disconnects the operating circuit of magnet 213, which is hereby prevented from being affected by succeeding impulses. The busy test relay 214 is also disconnected j aes-mear.

at the lowermost contacts of relay 206 to prevent a subsequent talse operation thereof. The communication circuit is now completed and extends from telegraph battery at the upper middle front contacts of relay 206, lower winding of relay 207, `contacts of switch 102 through the transmitting and receiving apparatus at station 100, returning through front contact-s of key 118 to the upper conductor of line 101, contacts o switch 102, upper winding of relay 207, upper outer front contacts of relay 206, brush 202, conductor 404, .through the vprinting apparatus at station 400, thence to ground through the right contacts of key 418. It will be noted that this circuit includes equally both windings of diierential relay 207, so that this relay is maintained deenergizedregardless of whether the printer signals are open signals or not.

The release of the established connection is completely under control of the subscriber at station 100. `When the communication has been completed, this subscriber restores key 118. The upper winding of diferential relay 207 is thereby shunted and the lower winding of this relay is energized by means of a circuit traceable from battery at the upper middle front contacts of rela 206, lower winding of relay 206, lower winding of relay 207, contacts of switch 102, through the dialingV and printing apparatus at station 100 to ground through the left normal contacts of key 118. Rela 207 thereupon opens its contacts and .atter an interval brings about the release of relay 204. Relay 204 at its upper contacts breaks the holding circuit of relay 206, which thereupon releases. Relay 206 upon releasing'removes ground from the conductor 403, rendering the line 401 idle and causing t-he deenergization ot' the upper windin of magnet 405. The. lower armatures of t is latter magnet are, therefore, retracted, thus closing the normal energizing circuit of control relay 409, whereby motor 411 is brought to rest. Immediately that relay 204 retracts its armatures, a circuit is completed from battery, through the windings of release magnet 216, lower contacts of oli-normal switch 211, lowermost back contacts of relay 204 to ground through back contacts of relays 205 and 206. By means of this latter circuit the brushes 202 and 203 are restored to their normal position. When switch 200 is restored to normal, the previously traced circuit for magnet 216 is broken at the lower contacts of switch 211, thus bringing brushes 202 and 203 to rest in their normal position. 1t will be noted that when relay 4204 releases, the holding circuit for magnet 105, which includes the upper winding of said magnet, contacts of switch 102, conductor,` 119 and kcontacts of relay 204, is broken when this latter relay releases, thuscausing the withschematically by a rectangle may manana drawal ot plunger 112 from the associated bank contacts. Wit-h magnet 105' deenergiaed the normal operating circuit of relay 109 is completed, and motor 111 is brought to rest.

`Eem?)Z'lslwnemf of a conference connection.

It will now be assumed that the subscriber at station 100 desires a printed message to be recorded at a plurality of separate stations, including station 400 and station 450. For this purpose the subscriber lirst dials the code 10. 1t will be understood that the apparatus at station 450 which is re resented be' duplicate apparatus to that shown in connection with station 100 and station 400. Similarly, the line 451 connecting station 450 with the central office terminates in the contacts of an individual line lswitch with its` associated control devices, represented schematically by the rectangle 460. This apparatus also may be in duplicate of corresponding` apparatus i. shown in Fig. 1.

From an inspection of Fig. 2, it will be noted that the line 224 leading from terminals 222 and` corresponding to the number 10, instead yof leading t-o a called station as 4 provided more4 thanl one conference num,

'main or line windings.

doesline 401, leadsto a series of telegraphv repeaters, 301, 501, etc. These repeaters ma be` of the general type described in U. lpatent to W. E. Athearn No. 774,905 issued Nov. l5, 1904. Reference maybe had -to this patent for a. detailed description of the construction and operation of vrepeaters 301, 501.y etc. It may be pointed out however that the lower windings of the relays 308, 309. 508, 509, etc. are the holding windings, and the upper windings are the As the external circuit for the left hand line windings 309, 509, etc is normallyopen at bank contacts 222. while the external circuits of the right hand windings 30.8, 508, etc. are normally closed, the operationl of the repeaters being as described in the Athearn'patent, the normal idle .condition of these repeaters is 4suoli as to maintain the right contacts closed and the lett contacts open. There may `be as many of these repeaters associated with the conference terminals tis-conditions may require. The drawings show two repeaters,

but it will be understood that others may be provided at the. points indicated by the dotted portion. of the conductors shown 1n Fig. 5. Furthermore, there may also be ber, .tor example. the dialing ot the number 20 will result in the seizure of line 223, which Vmay be associated with a greater or less number ot repeaters thanfare'" provided when thn line 224 is seized.

The sequence oitoperations when estab lishing the conference circuit is identicall with that already described, as far as the transmission of a printed busy signal tol the calling subscriber in a similar manner to that hereinbefore described.v The subscriber on noticing the busy indication may release the connect-ion anddial another con ference number, for example 20 resulting in the seizure of conference line 223 if this line is idle. f

Immediately that relay 212 releases, after thev dialing of the digit zero, a circuit is completed from battery through the winding of release control relay304, brush 203, upper back contacts of relay 212, lower winding of relay 206, upper back cont-acts of relay 214, to ground at the lowerinner contacts of relay 204. ARelays 304 and 206 operate. by means. of this circuit. Relay 206 also locks by means of its upper winding and locking contacts to ground at the upper contacts of relay 204, and yprovides a. holding circuit for relay 304. Rela F 206 also grounds the lower conductor of lin-e 224 lt0 render this line busy. Circuit is now completed from' telegraph battery at the upper middle contacts of relay 206, lower windino` of relay 207, inner right contacts of switci 102, through the substation printing and dialing apparatus. returning through front contacts of key 118, upper conductor of line 4 10.1, upper winding of relay7 207 upper outer .front contacts of relay 206, brush 202, upper conductor of line 224, upper winding. of relay 309, front contacts oi relay 308, conductor 521, through `the upper windings of intermediate repeater relays corresponding to relay 309, upper winding of relay 509, which is associated with the last repeater of the group, front contacts of relay 508 to ground. It is lto be noted that the repeaters are so arranged that normally the lower windings of relays 308, 508, etc.alone are energized to hold the corresponding contacts closed. Since the circuit through the line windings of relays 309, 509 is nornially, open at the connector bank terminals,

nos

contacts thereof to be opened. 'lhe contacts ot relay 30e are 'thus held closed by means ot the holding winding oit relay 308..

Under control. of the previously traced circuit, the armatures ol relays 309, 509, etc. are attracted to their iront contacts, whereupon a circuit completed from battery, through the .trent contacts of relay 300, upper winding of relay 303, uppermost back contacts of relay 312, winding or' relay l306, contacts relay 305 to ground through resistance 30'?. a similar circuit may e traced comprising the upper winding ot' relay 503 and the winding ot relay 505 to gro-und at the contacts of relay 505. Under control o t these latter circuits the armatures olf rela s 303 and 508 are respectively held attracted their front contacts independently oi their lowerwindings. Relays 300 and 506, as well as corresponding relays associated with any interinediate repeaters are energised by means off these last traced circuits. Relay 306 is alone, however, eective at this time and extends ground through its iront contact to operate the slow-to-release relay 311. rlhe correspondine circuit for each slow-to-release relay, similar to 511, associated with other connections, while closed at the front contacts of .the associated relay, such as 506, is opened at upper front contacts ot a relay simil-ar to relay 312 individual to the next preceding connector. A circuit is now prepared for the vertical magnet 313 and the associated slow relay 3111 traceable from battery, through the winding of said magnetand said relay in series, uppermost contacts ofthe oit-normal switch 317', lower inner contacts of relay 311, to the back contact of relay 306. rllhe circuits are not in readiness for the reception of the lirst oithe series oi impulses corresponding to the first digit, as dialed. by 'the subscriber. ln this case it may be assumed that the line l01'is the first line of the desired conference group. Accordingly., the subscriber n'ianipulates his dial to transmit a series of 3 impulses. ln response to the transmission ot the first im pulse the circuit hereinbe'tore traced comprising the telegraph battery at the upper middle contacts of relay 200 and the upper windings ot relays 309 and 509, etc, in series is broken vwhereby these relays are deenergized to cause their armatures to be re` tracted. rlfhe retraction ot the armature ot relay 300 breaks the circuit, hereinbetore traced, through the winding oit relay 300, which thereupon releases and extends ground through its bach Contact and the front contacts ol5 relay 311, uppermost contacts of switch 317 to battery through the winding oi relay 314 and magnet in series. ln response to this tiret impulse thc brushes 302 and 303 are posi ioned betore the rst level of terminals in switch 300 and the cul-normal switch 317 is operated.. Switch. 317 while opening the original stepping circuit for magnet 33 closes a sub-- stitute circuit therefor, comprising the winding and front contacts ot' relay 3111, the middle contacts of switch 317, iront contacts oi? relay 311, and baclr contacts of relay 306. Under control of 'this last circuit and the remaining 7 impulses, as transmitted by the device 107, the brushes 302 and 303 are positioned before the eighth level of terminals in switch 300. At the end oia this series ot impulses, relay 314C releases and transfers the stepping circuitto the winding ot rotary magnet 316 and the slow release relay 315. ln response to the transmission ot the next series oi impulses, in this case six, the brushes 302 and 303 are positioned in cooperative relation with the terminals 321, in which the line 101 terminates. it the end of this series ot impulses the line circuit is closed for suiiicient time to allow relay 315 to release.

During the interval between the seizure of line terminals 321 and the release of relay 315, and while this latter relay is maintain ing its armatures attracted, a test is made ot the line 401. lf this line is busy, the conductor 403 is grounded in the manner .liereinbefore described, and. relay 318, connected thereto by means of brush 303, is energized. `When relay 315 is released, relay 313 is locked by means of a circuit traceable trom battery, through the winding ot said relay, lowermost contacts of relay 312, normal contacts of relay 315, upper front contacts ot relay 313, outer front contacts ofrelay 311, to ground at the lower contacts ot relay 304. lll/'ith relay 318 locked, a circuit is completed from ground, through the contacts of interruptor 522, winding of relay 305, outer Yfront contacts of relay 318 to battery at the outer contacts of relay 315. Interruptor 522 is similar in construction to interrupter 215 and comprises conducting and insulating segments arranged in such a manner as to cause telegraphic impulses to be sent through the winding of relay 305- corresponding to the letter B or in some. cases to the word busy, lt desired a sinrle interruptor as 215 may be provided for oth types oi' connectors, Relay 305, therefore., correspondingly*attracts and retracts its armatures in accordance with the arrangement oi these segments. Accordingly, the circuit hereinabove traced comprising the winding ot relay 306, uppermost back contacts of relay 312, upper winding ot relay 308 and the front contacts of relay 309 is opened and closed, resulting in a corresponding release of the armature of relay 308. The contacts oi relay 303 in turn control the circuit including the upper winding of relay 309, and the upper winding of difierential relay 207, and characteristic impulses ya? or said relay, winding of relay 325, to

' of. the busy interrupter.

are transmitted to the receiving printer at station 100 in a manner similar to that herel inbefore described. The subscriber noticing the reception of Athis busy signal, opens lrey 1 08. The operation or key 108 opens the circuit hereinbei'ore described, through the line windings or relay 309 and 509 which thereupon release. Relay 309V in turn releases relay 306. After an interval relay 311 releases in turn releasing relays 318 and 305 to render ineffective further operation Relay 311 also closes a circuit for release magnet 323 traceable :trom battery, through the winding of said magnet, lower contact of the oit-normal switch 317, next to the lower inner contacts of relay 312, outer back contacts otrelay 311 to ground at the front contacts of relay 304. Under control of this circuit the magnet 323`restores the brushes 302 and 303 to their normal position whereupon magnet 323 becomes deenergized and the brushes `are brought to rest. Relay 304 does not release, however, since it is held operated by means of ground at the lower inner front contacts` of relay 206. When the subscriber restores key 108 the circuit comprising the line windings of relays 309, 509, etc., is reclosed, these relays reoperating. Relay 309 operates relays 306 and 311 and the stepping circuit for `magnet 313 is prepared as herembefore described. The subscriber now proceeds to dial the called number of any other desired i' station, as a result of which the brushes 302 and 303 are positionedupon the terminals of the line leading to this station and the driving motor thereat is set in operation. These latter operations have been described in detail hereinbefore and repetition at this int is not/considered necessary.`

Should the line 401v be idle when the ltevrminals 321 are seized by brushes 302 and 303,

as hereinbefo're described, the conductor 403 will be ungrounded and when relay 315 is releasing, the busy test relay 318 is connected to this conductor, but this relay remains operates, and the lower armatures of the.

magnet 405 are attracted, resulting in the release of the control relay 409 and the starting in operation of the motor 411. Relay 312 immediately closes a locking circuit under control 4of the upper contacts of relay 304. Relay 312 also completes` Ia circuit from battery through upper front contacts ground at upper middle back contacts of relay 512. Relay 325 operates and maintains a steady potential at the terminals ot relay 308 so that the printer 430 is'unatlected by succeeding selective impulses. The stepping circuit is successively transferred to the vertical and rotary magnets associated with succeeding repeater connectors of this conterence group, and the lines leading to the stations associated with conference number 10 are seized. The intermediate connectors are similar to the connector of Fig'. 3 and it is believed further description thereof is not necessary at this point.

lt will bel remembered that relay 506 is operated at the same time that relay 306 is operated. Accordingly, when relay 312 and corresponding vrelays of intermediate repeaters have closed their front cont-acts, a

circuit may be traced from battery, through the winding of relay 511, front contacts of relay 506, conductor 523, in series through the next to the upper inner contacts of all the relays similar to relay 312, 'associated with the preceding connectors, to ground at theupper contacts of relay 304. The stepping circuit may now be traced from battery., through the winding ot verticalmagnet 513,l winding of the slow release relay 514, upper c'ontacts ot the oil-normal switch 517, inner front contacts of relay 511 to the back contacts of relay 506. Since the line 451 ap pears inY the seventh levelof contacts in the connector switches, the subscriber at station 100 manipulates his impulse transmitter to send a series ot 7 impulses. In response to the transmission of the first impulse the cir.- cuit herenbefore traced comprising battery at the ipper middle contacts of relay 206, the lower winding of relay 207, contacts of the lineA switch, the apparatus at the sending substation, the upper winding of relay 207 and the windings ot relays 309 and 509 in series, is broken. Thus, the energizing circuit of relay 506 is also broken' and this relay .retracts its armatures, completing the previously described stepping circuit of magnet 513, whereby brushes 502 and 503I are positioned betoretheirst level of contacts in switch 500. The moving oit normal of brushes 502 and 503 operates the offnormal switch 517 and the stepping circuit for succeeding impulses may not be traced from battery, through the winding of magnet 513, winding of relay 514 and front contacts thereof, middle contacts of switch 517,

front contacts of-relay 511 and the back' contacts of relay 506, 'to the grounded conductor 523. Under control of the remaining 6 limpulses of this series, brushes 502 and 503 are positioned before the seventh level ot bank contacts. At the termination of the series, the line circuit is closed for a period sutliciently long to maintain relay 506 energized and to cause the release of relay 514.

'The stepping circuit is thereupon transerred to the rotary magnet 510 and may be traced from battery, through the winding of said magnet, back contacts of relay 512, thence in parallel through the slow-to-release relay 515, inner back contacts of relay 518, back contacts of relay 5111, middle contacts ot the oit-normal switch 5i?, Jiront contacts of relay 511 to the back contacts of relay 506. The subscriber thereupon transmits a series of 8 impulses, which by means ot' the bach contacts of relay 506 causes magnet 510 to rotate brushes 502 and 503 to the set ot' terminals 524 wherein the line 451 terminates. At the termination oit the transm mission of these 8 impulses, relay 515 begins to release and While said relay is releasing, a test is made of line 451. Il`he manner m which this test is made is similar to that already described in connection With the testing of line 401, and repetition thereof 1s not deemed necessary.

Should the last line of the conference group be busy While all the preceding lines ot the group are idle the calling subscriber receives a corresponding busy indication as hereinbefore described. The subscriber .may thereupon place the circuits in readiness lor communication by opening lrey 108 which results in the restoration to normal of switch 500 as above described. rlhe subscriber instead ol' dialing another subscribers num lier now dials the blank number 11, Whereby brushes 502 and 505 are brought to rest on the terminals 551. ii/'viren at the terminay tion ol the dialing` ot this number, relay 515 releases, circuit is completed trom battery nigh lrush 503, baclr contacts of relay 51., louer Winding ot relay 512,11pper bach contact of relay 510, lower 'iront contact relay till, conductor 532., to ground at the contact or relay e associated with the connector. 512 operates and loclrs through its upper uf'inding and inner trout contact, conductor 523, upper locking contacts o'l relays similar relay 512 associated with intermediate connectors, next to the .inner upper contact et relay 312 to ground at contacts ot relay i. llelay 512 opens the Circuit et overlap relay 325 and all similar relays associated with intermediate connectors thus ln'ealing the holding circuit ot the line windings ot repeater relays .308,` 50c, etc. lhe repeaters 301, 501, etc. are new in condition to repeat signal impulses to the respective call stations.

Should line 451, however, be idle when switch 500 was tirst operated, relay 512 `which is connected to the test conductor th/neoiz remains normal and when relay 515 releases, a circuit is completed jfrom battery, through toe upper Winding ot a magnet ir magnet d05, conductor 52, brush Jr bach contacts oli' 505, lower `#if relay upper bach contacts Leonesa of relay 518, outer front contacts of relay 511 to ground at the contacts of relay 304 associated with the first connector. The cutoil armatures of the line switch magnet associated with line 451 are thus attracted, resulting in the starting of the motor at station 4-50. Relay 512 also operates and completes a locking circuit for itself, Which may be traced from battery through the upper Winding and locking contacts of said relay,

to the grounded conductor 523. When relay' 512 operates, it releases relay 325 and corresponding intermediate relays to allow the repeaters 301, 501, etc. to repeat succeeding message impulses to the printers such as 430.

lVhen there are more than two repeater connectors associated with a conference line similar to line 224,- all the repeater connectors of the group are equipped similarly to the repeater connector shown in Fig. 3. The repeater connector shown in Fig. 5 has been illustrated as the last of the group associated with line 224. lt will be noted that there is no overlap relay associated with this connector corresponding to relay 325 associated with connector 300. The purpose of the overlap relay is, as noted hereinbefore, to prevent the switch operating impulses Which are delivered to the several repeaters from atlecting the printing apparatus on stations which have already been connected with by previously operated connectors until the last connector ol the group has been positioned. bviously, therefore, when relay 512 associated with the last repeuter connector operates, it is an indication that all the lines in the conference group have been seized and thatv the circuits are in readiness for the reception of printer impulses.

'l`he printer impulse repeating circuit may be traced 'from battery at the upper middle contacts or" relay 205, loner Winding of differential relay 20T, contacts of switch 102,:through the printing apparatus at station 100, returning through the upper Winding o' relay 207, brush 202, upper line Winding of repeater relay 309. closed contacts ot relay 308, conductor 521, line windings of intermediate repeater relays similar to relay 300, and closed contacts ot relay similar to relay' 308, line Winding of relay 500, to ground at the contacts of relay 508. Under control or" the printer impulses relays 309, 509, etc. attract and retract their armatures to repeat the impulse to the respective connected stations. The impulse circuit leading to station 400 may be traced from ground through the lett contacts of lzey 418, printing apparatus at station400, conductor 4:04,.

brush 302, upper outermost front contacts of relay 312, line Winding ol relay 308 to the armature ol relay 309.l Similar impulse repeating circuits may be traced to the other connected stations.

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' common to all of said stations, means responsive to the operation of saidautomatic means for interconnecting one of said stations with another of said stations, means responsive to such interconnection for operatively connecting the power source at said other station with its corresponding printing equipment.

2. In a telegraph exchange system, a plurality of subscribers stations, printing telegraph` transmitting and receiving -mechanisms and an impulse sending device at each station, a central oiiice, machine switching apparatus at said central office responsive to the operation of the impulse sender at one of said stations for automatically interconnecting said station with a desired one of the other stations, and means `responsive to the establishment of such an interconnection for immediately rendering the printing telegraph equipment at the desired station capable of receiving a printed message from the other station connected therewith.

3. In a telegraph exchange system, a plurality of subscribers stations, printing telegraph equipment and a source `or power therefor at each of said stations, said source of power being normally disconnected from its associated equipment, a central office, automatic switches at said central oflice, means under control of one of said stations to interconnect said one of said stations with a plurality of other stations, means responsive to such interconnection for immediately operatively connect-ing the power source yat each of said other stations with its corresponding printing telegraph equipment whereby printed messages may be imlmediat'ely received ateach of said plurality of stations, and means effective upon the discontinuance of the interconnection for disconnecting the power sources at said interconnected stations from the associated equipment.

4. In a printing telegraph exchange system, ay plurality of subscribers stations, printing vtelegraph equipment and driving means therefor at each of said/stations, said driving means. being normally inert, automatically and directively operable switches graph equipment at each station, a source of power for' each equipment normally disconnected therefrom, automatic switches, means under control of any of said stations for causing said switches to operate to interconnect two or more of said stations, and means responsive to the establishment of such an interconnection for operatively connecting the power source at certain of the interconnected stations with their corresponding telegraph equipments.

6. In a printing telegraph exchange system, a plurality of subscribers stations,

'printing telegraph equipment and a source of power therefor at each station, said power source being normally disconnected from the associated equipment, a lcentral oiiice, automatic switches at said central oice for establisli-in'g a plurality of simultaneous communication circuits to said stations, means responsive to the establishment of a communication 'circuit to a station and operable over said 'circuit for connecting the f source of power thereat with the associated equipment to render said equipment immediately ready to receive printed messages.

7: In a telegraph exchange system a plurality of subscribers stations, printing telegraph equipment and driving means therefor at eachstation, said driving means being normally inert, means for establishing a printing communication circuit from one station to any other station and means responsive to such establishment of a connection and operable over the communication circuit for starting the driving means at the connected station in operation.

8 In a telegraph exchange system, a plurality of subscribers stations, printing telegraphk equipment and a source of power therefor at each station, said power source .being normally disconnected from the associated equipment, means for establishing a communication circuit from one station to graph equipment and driving means therefor at each of said stations, said means being normally inert, acentral oiiice, communication lines extending from the stations to the central oiiice, automatic switches at the central office for, interconnecting the calling and called stations, and means responsive to the establishment of said interconnection and operable over the communication circuit for immediately rendering operable the driving means at the called station whereby the all@ associated equipment becomes ready to receive the printed messages.

10. ln a printing telegraph exchange system, a calling station, a plurality of other stations, an impulse sending device at each station, a central ollice, automatic switches at said central oliice, means under control of the sending device at said calling station for operating certain of said switches to connect said calling station with a first one of said plurality of stations, means for operating other switches to successively establish a connection between said calling station and the remainder of said plurality of stations whereby printed messages may be siinu'ltanen ously received from said calling station at each or" said plurality of stations.

ll. ln a telegraph exchange system, a calling station, a plurality of called stations, printing telegraph equipment and driving means therefor at each station, said driving means being normally inert, an impulse sending device for each. station, central odice automatic switches at said central oice, means under control oi the sending device at the calling station Aior operating said switches to establish communication circuits in succession bett. yn said calling station and said plurality o" called stations whereby printed ii'icssagcs troni the callin@` station may loe reed oneously on the equipments at said called stations, and means responsive to the establishment o3? each communication cir cuit to a. called station for immediately operating the driving means thereat.

l2. ln aprinting telegraph exchange systeni, a first station, a plurality of other stations, printing telegraph equipment and driving ineens therefor at eachn station, a plurality of automatic switches for complet ing communica-tion circuits to said plurality ot' stations, means under control of said iirst station for directively operating one of said switches to establish a communication circuit to one of said plurality oi" stations, means operable over said established circuit for starting the driving means at said one of said plurality of stations, means under control of said first station `for directively operating another of said switches to establish a communication circuit to a second one of said plurality of stations, means operable over said last mentioned established circuit for starting the driving means at the second one of said plurality of stations, and" means for simultaneously sending printed rn'iessages from said first station over said established circuits,to said rst and said second stations.

i3. In a printing telegraph exchange systein, a central silice, a calling station, a plurality oi called stations, an impulse sending device for each station, a line for each stag the same with the central ality ol connector switches at said cehtral. oliice ir'or completing communication circuits to said called` lines, means for automatically extending the calling sta tion line, means responsive to the sending of characteristic impulses from the calling station for associating with said extended line a predetermined number of connector switches, and means Linder control of the calling station for operating each of said associated connector switches in succession to establish circuits to a corresponding plurality of called stations.

14. In a telegraph exchange system, a central oliice, a calling station, a plurality of called stations, an impulse sending de vice for each station, a line for each station connecting the same with the central oiice, a plurality of connector switches at said central office for completing communication circuits to said called lines, means Jfor automatically extending the calling station line, means responsive to the sending of a special code of impulses from the calling station for associating with said extended line a predetermined number of connector switches, and means under control of the calling station for operating each of said associated connector switches in succession to establish simultaneous communication circuits to a corresponding plurality of called stations.

15. ln a printing telegraph exchange stem, a calling station, a plurality of called stations automatic switches for completing communication circuits to saidv called stations, means under control of said calling station for extending communication circuits therefrom to one ot' said automatic switches, means under control of the calling station for directively operating said one oi' said switches to extend the communication circuit to a particular called station, means effective when said particular station is busy for releasing said switch Without releasing the rest or" the connection and for allowing the calling station to reoperate said switch to complete a communication circuit to another ot' said stations.

16. In a telegraph exchange system, a calll ing station, a central oflice, a plurality of called stations, a plurality of connector switches at the central oliice for interconnecting said calling station and said called station, means controlled by the called station for operating a predetermined number of connector switches to establish communication circuits to a corresponding number of called stations, and `means effective when one of said stations is busy for allowing the calling station to release the corresponding connectorswitch Without releasing the other connector switches.

17. ln a telegraph exchange system, a plurality ot printing telegraph subscribers lines terminating at a central office, automatic switches at the central olrlce for intersiinultaneous communication.

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lll() Lacasse 'and also to repeat message impulses to the receiving mechanism at a plurality of stations.

' 19. In' a printing telegraph exchange system, a pluralityv tf stations, printing telegraph transmitting and receiving equipment at each station, a centraloiiice, automatic Switches-at the central office for completing communication circuits between said stations, re ating devices at the central oice accessi le in common to said stations and adapted f to repeat impulses from a sending device to control the operation of said switches and also to repeat message impulses from the tele aph equi ment at one of said stations tot e telegrap equipments at a plurality of i stations.

20. In a printing telegraph exchange system, -aJcallingstation, a called station,printv ing telegraph equipment atsaid stations comprlsing message transmittin and receiving mechanisms, an impulsesen ing ldevice for, each .of said stations, a switch for automatically extending a calling station line when messages are to be sent thereover, a plurality of connector switches, means vunder control ofthe sending device at the calling stationl for associating withthe extended line a predetermined number of connector switches, an

September, 1925.

impulse repeating device individualto each of said connector switches and adapted to repeatselecting impulses to control the associated switch and to repeat message impulses to telegraph receiving mechanism at a called station.

21. Ina telegraph system'7 a calling station, a plurality of called stations, a plurality of automaticswitches, a device associated with each switch `for repeatin selective impulses thereto, means for sen ing from said calling station selective impulsesto a first one ofsaid devices to selectively actuate the associated switch, means for sending from saidl calling. station through said rst device toa second one of said devices impulses to selectively actuate the switch associated with said second device, and means for rendering said first device unresponsive to the impulses transmitted therethrough.

22. 1n a telegraph exchange system, a calling station, a plurality of called stations, a plurality of automatic switches, a device associated with each switch for repeating se- .,lective impulses -thereto and for repeating messageimpulses to a called station, means for sending from said calling station selec-` tive impulses to a `first one of said devices to selectively operate the associated switch,

means controlled by the calling station for sending selective impulses throu h said rst device to a second one' of said devlces to selectively actuate the switch associated therewith, and means rfor temporarily short circuiting the first device while selective impulses are being sent therethrou h and for subsequently rendering said rst evice effective to repeat message impulses to a called station.

Intestimony whereof, I have signed my name to this specification this 8th day of DONALD' B. PERRY. 

